TRA / TPB is one of the most commonly used theories and has been applied to health behaviors for nearly 40 years. Thus, measurement of TRA / TPB constructs is well established.

This section will provide a brief introduction detailing common characteristics of TRA / TPB measurement, such as the types of scales used, the need for elicitation studies, and differences in direct and indirect measurement. Following the introduction, these characteristics of TRA / TPB measurement will be discussed in greater detail and specific to each construct.

Unipolar or unidirectional scales: very little control / complete control, not at all worried / extremely worried.

Scoring from -3 to +3 such that:

Belief that behavior will result in a positive outcome contributes positively to measure.

Belief that behavior will result in negative outcome contributes negatively to measure.

Elicitation studies: studies conducted to identify and select the content for the construct measures.

Example: Before behavioral beliefs can be measured, the researcher must know what they are for the health behavior and population studied.

It is always important to pilot test your measures / instrument

Direct measurement refers to measurement on a major construct (example: attitude, subjective norms, perceived behavioral control). These are usually more strongly associated with outcomes than indirect measures. Demonstrate these associations before proceeding to indirect measures.

Indirect measurement refers to measurement on the minor constructs that comprise the major construct and then calculating these scores across the outcomes of the behavior.